Premium water-mattress features 25 mil vinyl (25% thicker than most), deep moulded feather top pressure reduction surface for greatest comfort, lumbar support with 9-12-9 fibre layer waveless system - tethered to corners to prevent shifting, heater compatible bottom, bottom seams for greater durability, reinforced corners. Fits standard wood type waterbed frames. If you don't have a frame, frame building instructions included. Strobel Waterbeds are naturally fire resistant and do not require flame retardant chemical based flame barriers like other mattresses to comply with federal fire safety regulations. These mattresses are over 90% water. Strobel Waterbeds achieve nearly zero-gravity. Archimedes' Principle proved a body floating or submerged in a liquid is buoyed up by a force equal to the weight of the liquid displaced, thus the human body loses the amount of weight of the liquid displaced so that your body is lightened. This imposes less pressure on the body. Strobel Waterbeds go a step further with unique deep moulded ''Feather top'' pressure reduction surface. It relieves surface tension and further reduces pressures to allow true flotation sleep, so your muscles can truly relax. Strobel Hydro-Support waterbeds also feature reinforced corners, 4-way tethered waveless system to prevent shifting and thermally efficient heater compatible bottoms. Many people talk about the health benefits and how well they sleep on Strobel Waterbeds.